The present disclosure relates generally to medical devices and, more particularly, to methods of analyzing physiological parameters using wavelet transforms.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In the field of medicine, doctors often desire to monitor certain physiological characteristics of their patients. Accordingly, a wide variety of devices have been developed for monitoring many such physiological characteristics. Such devices provide doctors and other healthcare personnel with the information they need to provide the best possible healthcare for their patients. As a result, such monitoring devices have become an indispensable part of modern medicine.
One technique for monitoring certain physiological characteristics of a patient is commonly referred to as pulse oximetry, and the devices built based upon pulse oximetry techniques are commonly referred to as pulse oximeters. Pulse oximetry may be used to measure various blood flow characteristics, such as the blood-oxygen saturation of hemoglobin in arterial blood, the volume of individual blood pulsations supplying the tissue, and/or the rate of blood pulsations corresponding to each heartbeat of a patient. In fact, the “pulse” in pulse oximetry refers to the time varying amount of arterial blood in the tissue during each cardiac cycle.
Pulse oximeters typically utilize a non-invasive sensor that transmits light through a patient's tissue and that photoelectrically detects the absorption of the transmitted light in such tissue. A typical pulse oximeter may use light emitting diodes (LEDs) to measure light absorption by the blood. The absorbed and/or scattered light may be detected by the pulse oximeter, which may generate a signal that is proportional to the intensity of the detected light. The received signal may be further processed, and various physiological parameters may be determined based on signal features.
As certain signal features in the signal may be analyzed to determine physiological parameters, it may be beneficial to analyze the signal in a form from which various signal characteristics may be perceived. For example, some signal processing techniques include transforming the signal such that it may be analyzed in the frequency domain. However, such analyses may not provide information that is discernable in the time domain. Methods of processing the signal to perceive various signal characteristics in different domains, and methods of analyzing the processed signal may better enable the identification of physiological conditions based on a physiological signal.